"Why is it," the Air Force general asked Washington writing-consultant Pearl Aldrich, "that my officers present excellent oral briefings but their written reports are a disaster?"

"It's because they plan their oral briefings," suggested Aldrich, "and they don't plan their writing." Like a good many people whose jobs may require memo- and report-writing, they resort to a "memory dump."

"They dump the data on the pages as it's recalled in their minds," she says, instead of taking time to organize before putting words to paper. "That's why their writing is chaotic, why it's unreadable."

Many people who never planned to write in their careers -- such as engineers, accountants, computer specialists -- suddenly are promoted into a position where they find they have to. If they are unpracticed, says Aldrich, they may give into a kind of paralysis. They procrastinate and can develop tension headaches and stomach upsets.

"Though they have college degrees and are sure of their competence," says Aldrich, "their writing difficulties chip away at their confidence." In the end, the promotions may slow down or stop coming.

A free-lance writer and former newspaper reporter, Aldrich teaches business writing to government and corporate offices. She also offers a monthly six-hour "Saturday Seminar" to the public.

Clients frequently tell Aldrich they "hate" writing or that the task "frustrates" them or makes them "anxious." One of the most common complaints: "I often do not know where to begin."

One woman who sought her help, says Aldrich, had been assigned to write a manual of practices for her office. "Two months later, the material had piled up but she couldn't do it. Every time her boss asked, she was sick the next day."

An accountant who served as a financial liaison between his firm and government agencies often was required to make written reports to his president and board of directors. He would put it off for weeks and "then work 12 hours a day through six or eight revisions until he could finally let it go." This agony repeated again and again convinced him he needed help.

Another client felt that if she expressed her thoughts in simple language, "they'll think I'm simple."

Among myths Aldrich dispels in her classes:

* You must master the intricacies of grammar to be a better writer. "Nonsense," she says. "People apply the rules too rigidly. They get hung up with the business of not ending a sentence with a preposition."

* The more you revise a report, the better it becomes. False. "After the second or third time, you're at the point of no return. You get lost in jerking words around."

* The goal is "perfect writing." False, again. The perfectionists "tie themselves up in knots."

Her advice before you start to write:

* Identify the purpose of the report or memo. Among possibilities: "to persuade, to inform, to instruct, to justify, to strengthen ties."

* Analyze your audience. Who will read the report? Your boss may not need a lot of the background information you have collected. "If you are reporting on an experiment or an investigation, management doesn't want nuts and bolts. It wants results."

* Identify the point or points you want to make. As a rule of thumb to organize, "start with the items of greatest magnitude and go to the least."

Many nonwriters, says Aldrich, are unaware that it is up to them to do the organizing: The material does not necessarily fall naturally into a logical order. Even for professional writers, research material may be in chaos. "This is the nature of the beast."

As you write, keep in mind, she says, that the principal reason for your report or memo is to "tell people what to do next."

For more information on Pearl Aldrich's writing seminars (Saturdays, 9 a.m. to 5 p.m., $75): P.O. Box 7044, Washington, D.C. 20032. Phone 370-4044.